Closure plug



FIG. 1 is a plan view of a closure plug showing my new design;

FIG. 2 is a bottom view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a left side view thereof; and

FIG. 7 is a sectional view taken on line A--A of FIG. 1. 

The ornamental design for a closure plug, as shown and described. 